If so, we will make the changed Agreement available online at https://support.GOG.COM/hc/articles/212632089-User-Agreement and (if you have a GOG account) email you to let you know about the changes.</p> <p>We can change this Agreement but if we do we'll put the changed version online and normally it will take effect a reasonable time period afterwards.
It may be a bit concerning that GOG is only going to provide a “reasonable” period of time but did not actually specify the minimum period of time for the new changes to come into effect.